Glad you asked. The difference in color is due to different lighting conditions. The more... uh... "blue" was take indoors with a flash. The more turquoise hue was taken outdoors - either in shade or on an overcast day.

Since the subject has been raised... One of the fascinating things about the color is that it truly appears to change color. That's not at all what I meant to say; of course, it doesn't really alter it's state like a mood ring (remember those?). I mean that it is perceived differently depending on the light source. Indoors under typical household incandescent lights it can appear to be a rather deep Teal, but it will lighten to almost a Turquoise outdoors. No fancy prismatic embedded paint or metallic underlay involved, just plain old French enamel.